code: def test_pickle_frozen() -> None:
      """
      Regression test for the bug described in GPflow/GPflow#1338
      """
      module = D()
      module_frozen = gpflow.utilities.freeze(module)
  
      pickled = pickle.dumps(module_frozen)
      loaded = pickle.loads(pickled)
  
      assert loaded.var == module_frozen.var
      assert loaded.var2 == module_frozen.var2
      assert loaded.c.var == module_frozen.c.var
  
imports: import copy
  import pickle
  from typing import Any, Type
  import pytest
  import tensorflow
  import tensorflow_probability
  from check_shapes import check_shapes
  from packaging.version import Version
  import gpflow
  from gpflow.base import TensorType
label_desc: Use image node_id 3 for calling a global function with example usage: test_pickle_frozen() without return types